In general, a car is usually provided with at least one car-use audio device to execute the functions of receiving audio programs and playing multimedia. Going with the trend, the electronic device has already become an indispensable tool in daily life. Especially, when driving a car, for the purposes of getting instant traffic information, enjoying multimedia, and downloading data through internet, etc., people always take an electronic computing device installed with an operation system along. More often, the electronic computing device can be a personal computer (PC), a notebook (NB), a personal digital assistant (PDA), a mobile phone, a video game machine. It is certain that the electronic computing device installed with the operation system also can be an embedded computer, which is embedded into the car.
However, among the prior arts, the car-use audio device and the electronic computing device are usually provided individually. Therefore, it is necessary to control the car-use audio device and the electronic computing device via two individual operation interfaces respectively. Following up, the detail technology of the prior art will be disclosed with drawings.
Please refer to FIG. 1, which illustrates that the personal computer is controlled through a keyboard or a mouse within a car. As shown in FIG. 1, a car assembled with a car-use audio device 1, a sound playing unit 2, a main display 3 and speed monitoring module 4. The car-use audio device 1 comprises an operation interface 11 and a multimedia reading unit 12. The operation interface 11 has a plurality of function keys 111 and an operation display 112. The multimedia reading unit 12 usually can be a CD, VCD, DVD or MD reader. The sound playing unit 2 comprises a sound player 21 and a sound output terminal 22. The sound player 21 usually can be a car-use speaker, and the sound output terminal 22 is usually applied to communicate with an earphone or other sound playing members.
The main display 3 can be located within a receiving groove within the car-use audio device 1. The speed monitoring module 4 is applied to monitoring a moving speed of the car, and comprises a speed monitoring member 41, a speedometer 42 and a speed monitoring wire 43. The speed monitoring wire 43 is connected to the speed monitoring member 41 and the speedometer 42. Besides, an electronic computing device installed with an operation system is put in the car for a user to use, wherein the electronic computing device can be a PC, an NB, a PDA, a mobile phone, a video game machine, or an embedded computer being embedded in the car.
In FIG. 1, the electronic computing device is a PC 5, which comprises a PC host 51, a display 52 and two user-to-machine operation interface. The PC host 51 has a power on/off button 511 and a reset button 512, and the two user-to-machine operation interface are a keyboard 53 and a mouse 53a. 
In general, when the car is triggered to start, the car-use audio device 1 simultaneously enter a standby condition. In this moment, a user can operate one of the function keys 111 to make the main display 3 be extracted out along an extraction direction I, and rotated along a rotation direction II to an angle suitable for the user to watch. Following up, the user can operate the one or more of the function keys 111 to make the car-use audio device 1 to execute the preset assignments of playing audio programs, or playing multimedia read by the multimedia reading unit 12.
Moreover, when the user intend to using the PC 5, it is necessary to press the power on/off button 511 to boot the PC 5, and then input at least one working signal, via the keyboard 53 or the mouse 53a, to make the PC 5 execute at least one preset assignment. When the PC 5 is crashed, it is necessary to press the reset button 512 to reboot the PC 5.
People skilled in ordinary arts can easily realize that, in above prior arts, it is necessary to operate the operation interface 11 and the user-to-machine operation interface, i.e., the keyboard 53 or the mouse 53a, when the user need to control both the car-use audio device 1 and the PC 5. Meanwhile, when the user intend to use many different electronic computing devices, it is further necessary to operate different user-to-machine operation interface to control the electronic computing devices, and then brings more inconvenience.
Besides, when the PC 5 combines with a global positioning system (GPS), it is usually necessary to catch a speed data to execute the function of guided-driving. In the existed methods, the speed data is usually calculated from the relation of the coordinate data and the moving time. In practice, the movement distance calculate from the coordinate data is usually much different from the real movement distance that the car actually move, especially when it is under a bad signal receiving condition.